The treatment of chronic and non-chronic states of pain is of great importance in medicine. This is reflected in the large number of publications.
EP 0 693 475 discloses an active compound class of 3-aryl-butyl-amine compounds, in particular dimethyl-(3-aryl-butyl)-amine compounds, with an excellent analgesic activity and very good tolerability.
The preparation of these pharmaceutical active compounds starts from tertiary alcohols, these first being converted into the corresponding chloride compound, which is then reduced with zinc borohydride, zinc cyanoborohydride or tin cyanoborohydride. This process has the disadvantage that the preparation of the chloride compound takes place using comparatively aggressive chlorinating agents, such as thionyl chloride, and this furthermore also has to be used in a high excess. In addition, there is a considerable risk of fire and health hazard from the hydrogenation reagents. This process moreover does not proceed with a satisfactory yield in all cases.